微纳米钙钛矿型羟基锡酸钙的合成及对环氧树脂的阻燃性能

Synthesis of Micro-to Nano-scale Perovskite Calcium Hydroxytinate and Its Performance as a Flame Retardant in Epoxy Resin

钙钛矿型羟基锡酸盐是近年来出现的新型高效阻燃消烟剂.本文采用化学共沉淀法合成了微纳米钙钛矿型羟基锡酸钙[CaSn(OH)_(6),CSH],并利用扫描电子显微镜、透射电子显微镜、X射线衍射仪、红外光谱仪和X射线光电子能谱仪等对其形貌和结构进行表征.结果表明合成的CaSn(OH)_(6)为平均粒径500 nm的纯净正六面体,粒径均一且分散性良好.将CaSn(OH)_(6)应用于环氧树脂(EP)复合阻燃体系(CSH/EP),并分别采用热重分析、极限氧指数和锥形量热测试表征了其热降解行为和燃烧性能.采用扫描电子显微镜、红外光谱、X射线衍射和拉曼光谱对EP复合材料的阻燃成炭机制进行探索.结果表明,CaSn(OH)_(6)能显著提高EP复合材料的高温稳定性、热释放速率、热释放量、烟释放量和极限氧指数数值.特别是在很低添加量(0.5%,质量分数)下,阻燃消烟性能即得到极大提升,热释放速率、总放热量和一氧化碳释放量分别降低45.8%,25.1%和31.3%.此外,由于CaSn(OH)_(6)在EP基体中的良好分散及较强的界面作用,CaSn(OH)_(6)在提升EP复合材料阻燃消烟性的同时还提升了EP复合材料的力学强度.本文合成的CaSn(OH)_(6)可作为一种多功能的高效阻燃、消烟和增强剂.

Perovskite hydroxystannate is a new type of flame retardant and smoke suppressant with high efficiency that has appeared in recent years.In this paper,micro-to nano-scale perovskite-type calcium hydroxystannate[CaSn(OH)_(6),CSH]was synthesized by co-precipitation method.Scanning electron microscopy,transmission electron microscopy,X-ray diffraction,infrared spectroscopy,and X-ray photoelectron spectroscopy were used to characterize its morphology and structure.The results show that the synthesized CaSn(OH)_(6) was a pure regular hexahedron with an average particle size of 500 nm,and showed a uniform size and good dispersion.CSH/EP flame retardant composites were prepared by applying CaSn(OH)_(6) to epoxy resin(EP).Thermogravimetric analysis,limiting oxygen index and cone calorimeter tests were used to characterized its thermal degradation behavior and combustion performance,respectively,scanning electron microscopy,infrared spectroscopy,X-ray diffraction and Raman spectroscopy were used to explore the carbonizing flame retardant mechanism of EP composites.The results show that CaSn(OH)_(6) could significantly improve the high temperature stability,heat release rate,total heat release,total smoke release and limiting oxygen index value of the EP composites.Especially at very low addition levels(0.5%,mass fraction),the flame retardant and smoke suppression performance were greatly improved,and the heat release rate,total heat release and carbon monoxide release were reduced by 45.8%,25.1%and 31.3%,respectively.Moreover,due to the good dispersion of CaSn(OH)_(6) in the EP matrix and the strong interface effect,the addition of CaSn(OH)_(6) also improved the mechanical strength of the EP composite and enhanced its flame retarancy properties.The CaSn(OH)_(6) synthesized in this paper can be used as a multi-functional high-efficiency flame retardant,smoke suppression as well as a reinforcing agent for EP resin.